import turtle

t = turtle.Pen()

my_colors = ("red","green","yellow","black")

t.width(4)
t.speed(1)
for i in range(10): #0   1    2    3    4
    t.penup()
    t.goto(0,-i*10)    #0, -100,-200,-300,-400
    t.pendown()
    t.color(my_colors[i%len(my_colors)])
    t.circle(15+i*10)  #100,200,300, 400,, 500


turtle.done()   #程序执行完，窗口仍然在